Hydraulic broaching machine and work support therefor



K. c. MONROE Z,1134,5

HYDRAULIC BROACHING MACHINE AND WORK SUPPORT THEREFOR Filed March 5,1938 I 5 Sheecs-Sheet 1 warme R R39. K. c. MONROE HYDRAULIC BROACHINGMACHINE AND WORK SUPPORT THEREFOR Filed March 5, 1938 5 Sheets-Sheet 3l|.||||| llllhl I III-.IIII IIIII HI I I A my a A HYDRAULIC BROACHINGMACHINE AND WORK SUPPORT THEREFOR Filed March 5, 1938 5 Sheets-Sheet 4 uu n u %R. .ilnllllllllll IIIIIIIIIIIIIUwL cc. 1, 1939. K. c. MONROEHYDRAULIC BROACHING MACHINE AND WORK SUPPORT THEREFOR 5 Sheets-Sheet 5Filed March 5, 1958 lllllllll.l.ll V 11. I NM i 1:111 LII! IIL lwdefcy"like/i C. War/we I r "v Patented Dec. 19, 1939 UNITED STATES HYDRAULICBROACHING MACHINE AND WORK SUPPORT THEREFOR Kenneth C. Monroe, Hudson,Mass, assignor to The Lapointe Machine Tool Company, Hudson, Mass, acorporation of Maine Application March 5, 1938, Serial No. 194,191

2 Claims.

This invention relates to hydraulic broaching machines and to means forsupporting and holding a piece of work in such a machine. My inventionis shown herein as applied to a horizontal type of surface broachingmachine, but in certain aspects the invention is capable of more generalapplication.

It is the general object of my invention to provide power-actuatedcontrol devices in such a machine, together with electric interlocks sodesigned and correlated to said control devices that an impropersequence of operative steps in the use of said machine is renderedimpossible.

In particular, I provide control devices and electric interlocks soconstructed that a broaching stroke cannot be started until the work ispositively clamped in broaching position, and that a return stroke ofthe broach cannot begin until the work has been unclamped and removedfrom broaching position. It is also impossible to unclamp the work Whilethe main ram and broaching head are in motion.

I also provide means which requires the main reversible-discharge pumpto be shifted out of neutral position in a predetermined direction only,which direction is determined by the position of the operating parts.

My invention further relates to arrangements and combinations of partswhich will be hereinafter described and more particularly pointed out inthe appended claims.

A preferred form of the invention is shown in the drawings, in which:

Fig. 1 is a side elevation of a horizontal surface broaching machineembodying my invention;

Fig. 2 is an end elevation of the Work support, taken substantiallyalong the line 2-2 in Fig. 1; and

Figs. 3, 4, 5 and 6 are diagrammatic views showing the hydraulicconnections and electric interlocks in the positions which they assumeat successive points in the cycle of broaching operations.

Referring to Figs. 1 and 2, I have shown a horizontal broaching machineA and an associated work support C, said machine and work support beinglongitudinally aligned and rigidly secured together and beingparticularly adapted for surface broaching.

The broaching machine A comprises a base Ill supporting a main cylinderII in which a piston or ram I2 (Fig. 3) and a piston rod l3 areslidable. For purposes of illustration, the piston rod I3 is indicatedas extending through both ends of the cylinder ll, thereby simplifyingthe drawing by providing equal displacement at each side of the piston I2. This arrangement, however, forms no part of my invention, and inactual commercial use the double end piston rod would probably bereplaced by a single end rod,

with suitable means to take care of the unequal displacement, such meansbeing shown for instance in the prior patent to West, No. 1,685,760.

The machine A is provided with a main pump P which is preferably of thevariable-delivery, reversible-discharge type, also shown in a priorpatent to West, No. 1,722,832. A motor M is provided to continuouslyrotate the pump P but the discharge of the pump may be varied from zeroto full-discharge in either direction by means of a hand lever l5 or byhydraulic control devices to be described.

The work support C is provided with loading and discharge side platformsI1 and I8, and with a fixed overhead structure providing abutments I9against which the work W may be clamped.

The work support also comprises a hydraulic cylinder 20 and piston 2|connected by a piston rod 22 to a vertically movable work-supportingmember 23. If oil under pressure is admitted below the piston M, thework W Will be raised and clamped against the abutments I9 and will berigidly held in this position during the broaching operation and as longas the pressure in the lower end of the cylinder 20 is maintained. Thework W is indicated herein as an engine block in which the surfaces Sare to be finished in the broaching operation.

The longitudinally extended portion 24 of the work support C provides aslide or runway for the member to which the inverted surface broach issecured.

Fig. 3 is a diagrammatic view of the various hydraulic and electricfeatures of my improved broaching machine, with the parts shown inloading position.

The pump P is connected by pipes 30 and 3i to the two ends of the maincylinder II. The direction and rate of discharge is controlled by a rackbar 32 connected by a rod 33 to the hand lever I5.

The rod 33 is also connected by a lever 34 to a piston 35 in apump-control cylinder 33, and by a lever 31 to a knock-ofi' rod 38. Therod 38 is provided with collars 39 and 40 which may be adjustablypositioned on the rod 38 for engagement by a knock-off arm M on thepuller head 42 which is mounted at the end of the piston rod l3 and towhich the broach B is secured.

A locking device 44 is provided for the pumpshifting rack bar 32 andcomprises plungers t5 and 46 alternately movable into position forengagement by a block 4'! on the rack bar 32. The plungers are operatedby pistons slidable in cylinders which are cross-connected so that ifpressure is applied to raise one piston and plunger, the other pistonandplunger will be depressed.

The locking device 44 is connected by branch pipes 50 and 5| to pipes 52and 53 by which a solenoid-operated valve V is connected to the oppositeends of the work-clamping cylinder 20 previously described. Oil underpressure is supplied to the valve V from an auxiliary pump P through acheck valve 54 and needle valve 55, and the excess discharge of the pumpP is exhausted through a relief valve 56. Oil discharged from thecylinder 2|] through the valve V passes to storage through an exhaustpipe 51.

The pump-control cylinder 36 is connected by pipes 60 and 6| to asolenoid-operated valve V which is similarly provided with an auxiliarypump P needle valve 62, relief valve 63 and exhaust pipe 64.

The valves V and V are each provided with solenoid coils in each end bywhich the Valve may be drawn or shifted in either direction. The valve Vremains in shifted position until a reverse pressure is applied but thevalve V returns to mid or neutral position as soon as circuit is broken.

The parts above described constitute the essential hydraulic andmechanical elements of my improved broaching machine and its associatedwork support.

The electrical interlock for my improved machine comprises line wires1i] and H to which current is supplied from. any suitable source ofpower. The line 1| is connected to one side of each of the two solenoidcoils in each of two shunt circuits which control signal lights G and R.

Six switches D, E, F, H, K and L are utilized in my electric interlock.The switches D, H and K are hand-operated switches, designed to bemomentarily closed by the operator at different points in the sequenceof operations. The switch L is a double switch associated with theworkclamping cylinder 20 in such manner that an upper part of the switchwill be closed when the work is unclamped and lowered, and a lower partof the switch will be opened under the same conditions. When the work israised and clamped, the connections are reversed and the upper part willbe open while the lower part is closed.

The switches E and F are also double switches, each controlling twocircuits, and each of these four circuits includes one of the solenoidcoils in the valves V and V. Both parts of the switch F are closed whenthe pull head 42 is in its extreme left-hand position and ready to beginthe working stroke, as shown in Fig. 3. Both parts of the switch E areclosed when the puller head &2 is in extreme right-hand position andready to start the idle or return stroke, as. indicated in Fig. 5. Allcircuits through both switches E and. F are open when the puller head 42is in any intermediate position, during either the working or the returnstroke of the head, as indicated in Fig. 4.

The normal position of the hydraulic control devices and electricinterlock, with the machine in idle or loading position, is as shown inFig. 3, with the pump P in mid or neutral position, the piston 25 inlowered position in the work-clamping cylinder 20, the double switch Eopen, the double switch F closed, the hand switches D, H and K open, theupper part of the switch L closed, and the lower part open.

The sequence of steps by which a broaching operation is performed willnow be described. Assuming that a new piece of work W has been placed onthe work-supporting member 23, the operator closes the hand switch H,thus completing a circuit from the line wire 10 through a branch wire72, the lower part of the switch F, a wire E3, the switch H, and a wire14 to the left-hand solenoid of the valve V, and back through a branchwire N to the line wire Ii.

This causes the valve V to be shifted to the left, supplying pressurethrough the pipe 52 to the lower end of the cylinder 26! and raising thework W against the fixed abutments 59. When pressure is thus appliedthrough the pipe 52 to the lower end of the cylinder 20, similar pressure is applied through the branch pipe 55 to reverse the positions ofthe locking plungers 45 and 4t and to move said plungers to thepositions shown in Fig. 4. The application of pressure to the lower endof the cylinder 20 also reverses the connections through the switch L,as indicated in Fig. 4, and closes the lower part of said switch L.

If the hand switch D is then closed, the line wire it is connectedthrough the wire 15, switch F, wire 16, switch L and wire 7'! to theleft-hand solenoid of the valve V and thence to the line wire H. Thesignal G is also lighted. These connections are as shown in Fig. 4,except that the switch F is still closed.

The valve V then shifts to the left and supplies pressure through thepipe 68 to the lefthand end of the pump-control cylinder 36, causing thepiston to shift the pump P to the position shown in Fig. 4, in whichposition the pump discharges oil into the left-hand end of the maincylinder I I. This causes the piston or main ram 12, puller head 42 andbroach B to move to the right in a working stroke.

As soon as. this working stroke begins, the switch F opens, thusbreaking the previously closed solenoid circuits through the left-handends of the valves V and V, even if the hand switches H and D are heldclosed, which however does not ordinarily occur. The signal G goes outas the circuit of the solenoid in the valve V is broken.

The valve V remains in its left-hand position, thus maintaining pressureon the pipe 52, but the valve V returns automatically to mid or neutralposition, with both ends of the cylinder 36 connected to the exhaust.This exhaust connection is essential, as otherwise the mechanicalknock-off could not operate.

As the working stroke of the puller head 42 to the right is completed,as shown in Fig. 5, the puller head 42 closes both parts of the doubleswitch E, and the arm A! engages the collar 48 on the knock-01f rod 38and shifts the pump P back to the mid or neutral position shown in Fig.3 but with the locking plungers 45 and 46 still in the reverse positionshown in Fig. 4. It is thus impossible to shift the pump beyondmidposition, either automatically or manually, so that no returnmovement of the ram I2, puller head 42 and b1 oach B can be started.

The operator then closes the hand switch K (Fig. 5) completing a circuitfrom the line wire iii through the wire '52, switch E, wire 8%, switch Kand wire 8| to the right-hand solenoid in the valve V and thence throughthe branch wire li to the line wire N. This causes the Valve V to shiftto the right, admitting pressure through the pipe 53 to the upper end ofthe cylinder 28 and causing the work-supporting member 23 and work W tomove downward out of the path of the breach B. At the same time theconnections through the switch L are reversed, the upper part of theswitch now being closed and the lower part open. Admission of pressureto the pipe 53 also admits pressure to the branch pipe 5i returning thelocking plungers do and it to their original positions, as shown in Fig.3.

If the operator new closes the hand switch D a second time, as indicatedin Fig. 5, a circuit will be completed from the line wire id through theswitch D, wire branch wire it, the upper part of switch wire 8 upperpart of switch L and wire to the right-hand solenoid in the valve V andthence to the line wire ii.

This lights the signal R and causes the valve V to shift to the right,admitting pressure through the pipe 5? to the right-hand end of the pumpcontrol cylinder 3% and causing the piston 35 to shift the pump to theposition shown in Fig. 6, thus discharging oil into the right-hand endof the main cylinder ii and acting on the piston iii to move the pullerhead 42 and breach B to the left in a return stroke.

As soon as this return movement begins, the double switch E opens,breaking the circuits through the two right-hand solenoids in the valvesV and V, even if the switches D and K have not been released. When thesecircuits are broken, the valve V continues to maintain pressure in thepipe 53 and branch pipe as, but the valve V shifts to mid or neutralposition, in which both pipes 533 and 65 are connected to the exhaustpipe 6 As the return stroke is completed, the arm ii engages the collar39 on the knock-off rod 38 and returns the pump and associated parts tothe mid or neutral position shown in Fig. 3. Also as the return strokeis completed, the double switch F is closed, thus putting the parts insuch position that a new cycle of operations may be initiated by closingthe switch H as previously described.

It will thus appear that my improved broaching machine and work supportare so controlledand interlocked that no improper sequence of operationscan take place. More specifically, the breaching stroke cannot bestarted until the work is elevated and clamped in working position,which reverses the connections to the switch L. The work cannot beunclamped until the working stroke is completed and the switch E isclosed. It is then necessary to unclamp the work by closing the switch Kin order to return the switch L to its initial position and also toreverse the locking plungers 45 and i5, otherwise the pump cannot beshifted to reverse position for a return stroke.

It should be particularly noted that no circuit in the machine can becompleted unless the puller head 42 is in one or the other of itsextreme positions, as every circuit must be completed through the switchE or the switch F, both of which are open when the puller head is in anyintermediate position.

The pilot or signal lights G and R are provided for the convenience andprotection of the operator, the light G signifying that the workingstroke is about to commence and the light R signifying that the returnstroke is about to commence.

While I have described the machine as semiautomatic and requiring thecooperation of the operator in manually closing the switches D, H and Kat different points in the working cycle, one or more of these switchesmay be permanently closed, thus rendering the machine more fullyautomatic. For instance, if the switch D is permanently closed, theclamping of the work and the performance of the breaching stroke willfollow automatically when the switch H is closed. Similarly, theunclarnping of the work and the performance of the return stroke willfollow automatically when the switch K is closed. If the switches D andK are both permanently closed, the entire sequence of operations ofclamping, breaching, unclamping and return will be performedautomatically when the switch H is closed.

While more fully automatic operation may thus easily be attained, it isfound in most cases that the semi-automatic operation first described ismore satisfactory, as the machine is more directly under control of theoperator. The outstanding advantage of my improved machine, howeveroperated, lies in the fact that all operative steps must follow inproper sequence and that no operation can take place in such manner thatinjury to the machine, the tools or the work can occur.

In a machine of this type, the breach is commonly not removed from themachine at any time, and it is accordingly very desirable that returnmovement of the breach be rendered impossible until the finished workhas been lowered out of operative position.

Having thus described my invention and the advantages thereof, I do notwish to be limited to the details herein disclosed, otherwise than asset forth in the claims, but what I claim is:

1. A hydraulic surface-breaching machine comprising a breaching head, astationary abutment, a device to support a piece of work, means to raiseand lower said work-supporting device and work and to firmly press andhold the work in raised breaching position against said stationaryabutment, thereby simultaneously clamping and positioning said work,means to actuate said breaching head, and interlocking mechanismoperable with said several means to prevent a working stroke of saidbreaching head until the means for actuating the work-supporting devicehas raised and clamped the work in abutment-engaging position, andoperable thereafter to prevent return movement of said breaching headuntil said means for actuating said worksupporting device has loweredthe work from abutment-engaging position.

2. A hydraulic surface-breaching machine comprising a breaching head, astationary abutment, a device to support a piece of work, means to raiseand lower said work-supporting device and work and to firmly press andhold the work in raised breaching position against said stationaryabutment, thereby simultaneously clamping and positioning said work, aconstant-delivery pump to actuate said raising and lowering means, areversible pump to actuate said breaching head, a control valve forshifting said reversible pump, which valve automatically returns toneutral position when released, a mechanical knock-off effective toshift said reversible pump to neutral position after said control valveis released and has returned to neutral position, and means to preventmovement of said reversible pump to return said breaching head toinitial position until the means for actuating the work-supportingdevice has lowered the work from abutmentengaging position.

KENNETH C. MONROE.

